<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        function GetMax(num){
            var max=num[0];
            for(var i=0; i<num.length;i++){
                if(num[i]>max){
                    max=num[i];
                }
            }
            return max;
        }
        console.log(GetMax([5,2,99,101,67,77]));
    </script>
</body>
</html>